The objectives of this project are: (1) to develop improved or optimal human dental plaque dispersion methods using sonication techniques, different gaseous environments, or the addition of chemical-enzymatic additives to the dispersion solution; (2) to assess the role of colony crowding on agar plates upon colony morphology and the selective inhibition of certain streptococci on frequently used agar plates; (3) to evaluate selective broths as rapid presumptive tests for the presence of S. mutans in plaque samples.